Good points about the goldcard. Too many people end up unable to recover because they didn't make one, since it's not necessary just for rooting.
This bit about the kernel:
Its basically an interface that sits between the Android OS and the hardware. Almost like an interpreter.
Not really, it's the the heart of the operating system (hence the name, like the kernel of a nut, the most important part of anything). It provides the environment for the phone's software to work, including access to the hardware.